It is estimated that 3-5 percent of children suffer from fecal incontinence. One of the most effective ways of treating encopresis is through Enhanced Toilet Training (ETT). ETT is twice as effective as intensive medial management alone at 3, 6, and 12-month follow-up when delivered by skilled and knowledgeable clinicians. Although this finding is a clear indication that ETT can be effective in treating encopretic children, there are 5 major barriers to its implementation: 1) availability of a knowledgeable and skilled clinician, 2) parental acceptance of referral to a mental health professional, 3) expense for this available service, 4) burden of time and distance to access such specialty services, and 5) child resistance to disclosure of embarrassing material. We have attempted to circumvent these barriers by operationalizing the treatment components of ETT in creating an interactive Internet-based program, which we demonstrated significantly enhances treatment provided by primary care physicians. We have developed a theoretical model for therapeutic behavior change achieved by web-based interventions, and completed a feasibility study demonstrating the acceptance, function and effectiveness of such an intervention for children with encopresis. We propose a 5-year, 4-phase project: Expert Optimization Phase 1 will bring together clinical and website experts to identify optimal web and treatment elements as well as issues in need of experimental investigation. Experimental Optimization Phase 2 (years 1-2) will investigate how to enhance internet-based interventions with a series of experimental investigations. Clinical Trial Phase 3 (years 3-4) will evaluate the relative benefit of adding the internet treatment to clinical services provided by generalists and specialists in the fields of medicine and mental health. Cost-Benefit/ Dissemination Phase 4 (Years 4-5) will investigate the relative long-term benefits of adding such an internet based intervention to professional interventions, to determine impact on symptom improvement, generalization of symptom impact, relapse prevention, quality of life, and cost-effectiveness. Phase 4 will also assess to what extent the program is disseminated world wide when made generally available on the Internet. After 5 years we will have documented basic elements and dissemination patters of web-based pediatric behavior change programs generally, and, in particular Enhanced Toilet Training.